Okay, this isn't the same old Boy scout Supes vs "in over his head because he's a little kid" Captain Marvel.
7 years in the future, Billy Batson is a teenager. He gets all the hormones and angst that comes with the territory. He lashes out, is continually angry, and becomes a severe problem child.
Billy changes into Cap M. and all his teenage rage goes with him. Superman begins to lecture him about some sort of thing and Billy flips out.
How does THIS Captain Marvel fare against Superman, throwing all his angst and rage into him without holding back?
Already happened in POS 46, superman stalemated him while trying to talk him down. Superman although less holding back stalemated a all out cap in MOS 102. Superman 6/10.
It would be nearly impossible to prove CM is faster than Superman, though I'd love to see someone try (in all seriousness). Based on feats, it's perfectly clear Superman is faster. By a lot.
NAh if supes tries to range him hes toast. billy will zap him with shazam thunder bolts. BIlly is fast enough to avoid supes and prevent the absolutly retarded grab fest supes pulls to revert billy into his teenage form. Personally never seen billy lose control so dont know what will happen. And dont want to hear the crap about supes rushing billy and grabbing him to convert him to billy. AT range cap on his game supes is not fast enough for marvel to not see this coming. Supes has a slight speed advantage but its not like alot. Supes has shown weakness to billys magical lighting. I havent seen billy show much weakness to HV.
In combat yes. Now we use a characters entire history as evidence and not just the times Superman has fought CM. Thus using Superman's entire history he is significantly faster in combat. Also he can become intangible, something CM can't do.
Even assuming they have the same combat speed then Superman would still be tens to hundreds of times faster by simply slowing CM down a little with freeze breath. Supes known to multi task his powers in combat which is a huge advantage against CM.